Microbial cultures are used extensively in the food, feed and pharmaceutical industry in the manufacturing of fermented products including most dairy products such as cheese, yoghurt and butter, but also in meat, bakery, wine or vegetable products. Additionally, specific microbial cultures may be used as probiotic agents and formulated as tablets, capsules etc and provided to animals including humans for their general health improving effects. Thus, microbial cultures may be provided for several purposes they do, however, all need to be cultivated prior to any delivery.
The production of a microbial organism involves the inoculation of microbial cells in a specific fermentation medium with an appropriate number of the cells to be propagated under appropriate fermentation conditions. Obviously, a high concentration of microbial cells is desired at the end of the fermentation. Thus, the fermentation process i.e. the fermentation conditions and the fermentation medium, are sought optimised in order to have a cost effective production resulting in a high biomass yield.
Industrial fermentations are carried out using complex undefined fermentation media. Major components of such media can be yeast extract, cornstarch, whey protein or other milk based media, which all have complex compositions. For selected fermentations chemically defined media are used. Often, the composition of the fermentation medium may be optimal for the viability of the microbial cells, but not optimal for obtaining a high biomass yield of the microorganism.
There have been various conventional approaches to provide methods for the optimisation of the fermentation media for obtaining increased biomass yields including chemical analysis, removal and/or addition of single components, various fermentation types, optimisation of the fermentation conditions such as temperature and pH, mutant selection and genetic engineering of the microorganism.